The present invention relates to methods for building three-dimensional (3D) objects. In particular, the present invention relates to methods for generating build sequence data for building 3D objects with layer-based additive techniques.
Rapid prototyping/rapid manufacturing (RP/RM) systems are used to build 3D objects from computer-aided design (CAD) models using one or more layer-based additive techniques. Examples of commercially available layer-based additive techniques include fused deposition modeling, ink jetting, selective laser sintering, electron-beam melting, and stereo lithographic processes. For each of these techniques, the CAD model of the 3D object is initially sliced into multiple horizontal layers. For each sliced layer, a build path is then generated, which provides instructions for the particular RP/RM system to form the given layer. For deposition-based systems (e.g., fused deposition modeling and ink jetting), the build path defines the pattern for depositing roads of build material from a moveable deposition head to form the given layer. Alternatively, for energy-application systems (e.g., selective laser sintering, electron-beam melting, and stereo lithographic processes), the build path defines the pattern for emitting energy from a moveable energy source (e.g., a laser) to form the given layer.
In fabricating 3D objects by depositing layers of build materials, supporting layers or structures are typically built underneath overhanging portions or in cavities of objects under construction, which are not supported by the build material itself. A support structure may be built utilizing the same deposition techniques by which the build material is deposited. The host computer generates additional geometry acting as a support structure for the overhanging or free-space segments of the 3D object being formed. The support material adheres to the build material during fabrication, and is removable from the completed 3D object when the build process is complete.
While layer-based additive techniques provide durable 3D objects with high resolutions, there is an increasing demand for 3D objects containing embedded inserts, where the embedded inserts are not necessarily fabricated with the layer-based additive techniques. For example, consumers may request 3D objects containing pre-inserted bolts for allowing the 3D objects to be subsequently secured to other components. A common issue with the use of embedded inserts is generating the build data for the 3D objects that contain the embedded inserts. As such, there is a need for methods for building 3D objects containing embedded inserts that allow for accurate placements of inserts during the build operations.